For most people, the nature of labor has greatly changed. Not too long ago, many workers were exposed to hazardous materials and deplorable conditions. Many a heavy load was carried on the back of a laborer. Today's workforce would be barely recognizable by those manual laborers. We now sit at computers, click on our mice and type away at the keyboards. While seemingly non-injurious, long-term computer use has created a whole new class of workplace injuries. For example, many people that type at computer keyboards for long periods of time, such as secretaries and word processing specialists, suffer from repetitive stress injuries to their wrists and fingers. Many of those same workers also suffer from back and neck strain from looking at their computer monitors.
Eyestrain also is sometimes experienced after extended viewing of computer video display monitors. Several factors contribute to eyestrain including glare, insufficient screen resolution, and poor lighting. Other contributors to eyestrain include excessive screen brightness as well as flicker.
Flicker is commonly associated with the vertical refresh rate of the video display monitor. In particular, when the vertical refresh rate of the video display monitor is close to a frequency of oscillating light emanating from ambient sources, such as overhead fluorescent lights, the display on the video monitor tends to flicker. Flicker is annoying and can cause eyestrain.
While conventional video display monitors use software to select a vertical refresh rate, the selected vertical refresh rates typically fail to account for actual use conditions. For instance, some countries use different conventions for carrying electrical current. European countries use a 50 Hz cycle current while the United States uses 60 Hz as a working frequency. Moreover, some working environments may include other light frequency sources that impinge on a video display monitor. Video monitors that fail to account for these differences and factors are more likely to produce flicker.
Given these considerations, there is still much room for improving the quality of images displayed on a video display monitor.